The prevention of unauthorized entry of vehicles to a facility has increased in importance in the recent past. For example, recent experience has indicated that terrorists will crash an explosives laden vehicle into a building in order to cause destruction of same. The primary defense against such attacks is a barricade which effectively stops the oncoming vehicle at a safe distance from the building. The barricade chosen must be movable in order to permit authorized entry, while preventing unauthorized entry.
Numerous barricades have been proposed for preventing unauthorized access to a facility by transit along a roadway. Generally, such barricades include a barrier plate which is pivotal between an extended position and a lowered passage position. The barrier plate is usually pivoted by mechanical mechanism, such as an hydraulic cylinder and piston.
As noted, the barrier should permit authorized access, while preventing unauthorized access through rapid pivoting into the extended position. Should the plate not pivot quickly enough, then the onrushing vehicle may obtain access. Furthermore, the observation booth is frequently remote from the barricade and it is therefore necessary that the barrier be remotedly operated. Furthermore, operation of the barrier in any one of a number of various emergency conditions which may arise must be assured.
The disclosed invention is an hydraulic barricade and method which is operable through a primary active motive force, as well as through a secondary passive motive force. The secondary source is activated through a valve having a manual/remote operator to permit pivoting in an emergency situation, such as loss of power, loss of fluid or terrorist attack. Regardless of the condition, the disclosed hydraulic barricade may be rapidly operated by either of the sources in order to effectively stop the oncoming vehicle.